| From: | Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> |
|---|---|
| To: | aditya desai <admad123(at)gmail(dot)com> |
| Cc: | Pgsql Performance <pgsql-performance(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: SELECT Query taking 200 ms on PostgreSQL compared to 4 ms on Oracle after migration. |
| Date: | 2021-04-03 13:47:47 |
| Message-ID: | CALj2ACXN9ZohCxP-y-5qwNrHKP4y3_aNqm=usZ=YPZEiEEpiyw@mail.gmail.com |
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| Lists: | pgsql-hackers pgsql-performance |
On Sat, Apr 3, 2021 at 7:08 PM aditya desai <admad123(at)gmail(dot)com> wrote:
>
> Hi,
> We migrated our Oracle Databases to PostgreSQL. One of the simple select query that takes 4 ms on Oracle is taking around 200 ms on PostgreSQL. Could you please advise. Please find query and query plans below. Gather cost seems high. Will increasing max_parallel_worker_per_gather help?
No it doesn't. For small tables, parallelism might not help since it
doesn't come for free. Try setting max_parallel_worker_per_gather to 0
i.e. without parallel query.
With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com
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